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| Rankin temperature equals ? |
F + 460 |
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CAVUMark Thu, 19 Feb 2009 06:08:52 GMT |
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| Absolute pressure equal |
PSIG +14.7 |
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CAVUMark Thu, 19 Feb 2009 06:08:52 GMT |
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| What is the general gas law? |
PV/T (sub1) = PV/T (sub 2)
OR
P1V1T2 = P2V2T1
Pressure and temperature are absolute. |
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CAVUMark Thu, 19 Feb 2009 06:08:52 GMT |
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| What is the Volume formula? |
Volume = area x length
VAL |
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CAVUMark Thu, 19 Feb 2009 06:08:52 GMT |
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| What is the FORCE formula? |
Force = area x pressure
FAP |
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CAVUMark Thu, 19 Feb 2009 06:08:52 GMT |
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| What is the weight of a cubic foot of water? a cubic inch of water? |
62.4 lbs for a cubic foot, 0.03611 lbs for a cubic inch. |
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CAVUMark Thu, 19 Feb 2009 06:08:52 GMT |
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| When does the maximum density of water occur? |
At 4 C. |
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CAVUMark Thu, 19 Feb 2009 06:08:52 GMT |
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| Is density affected by temperature? |
YES. An increase in altitude will decrease air density. |
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CAVUMark Thu, 19 Feb 2009 06:08:52 GMT |
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| Specific Gravity = formula |
weight of substance/weight of same volume of water. AND
density of substance/density of water |
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CAVUMark Thu, 19 Feb 2009 06:08:52 GMT |
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| What is specific gravity? Of water? |
SG is the ration of densities, density of a substance compared to water. Water is 1.0 |
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CAVUMark Thu, 19 Feb 2009 06:08:52 GMT |
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| What are a gases properties? |
no definite shape,
assumes shape of container
fills container completely
readily transmits pressure
compressible
Lighter than equal volumes of liquid |
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CAVUMark Thu, 19 Feb 2009 06:08:52 GMT |
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| What are a fluids properties? |
not compressible
easily transmits pressure
assume shape of vessel
defined shape |
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CAVUMark Thu, 19 Feb 2009 06:08:52 GMT |
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| What are 6 advantages of hydraulic systems? |
Efficient
lightweight
ease of installation
rapid start/stop
simple to inspect
minimum maintenance |
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CAVUMark Thu, 19 Feb 2009 06:08:52 GMT |
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| What is an important service reminder for hydraulics? |
All systems OFF unless called for by A/C maintenance Manual. |
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CAVUMark Thu, 19 Feb 2009 05:53:26 GMT |
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| What are a turbine engines safety zones in feet? Front, back? |
Front = 25 feet
Back = 100 feet @ idle
250 - 350 @ take off power. |
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CAVUMark Thu, 19 Feb 2009 05:53:26 GMT |
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| How is a pneumatic line marked? |
Color code: Red/Blue
verbage: Pneumatic
Graphics: diamond, black on white |
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CAVUMark Thu, 19 Feb 2009 05:53:26 GMT |
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| How is a line marked that contains Hydraulic fluid? |
Color code: Blue/Yellow,
verbage: Hydraulic
Graphics: circle black on white |
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CAVUMark Thu, 19 Feb 2009 05:53:26 GMT |
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| What additive is included with MIL-H-5606? Any hazards? |
Petroleum based 5606 includes TCP, tricresyl phosphate - anti wear. This can be absorbed through the skin and cause paralysis if taken internally. |
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CAVUMark Fri, 13 Feb 2009 06:16:52 GMT |
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| Is MIL-H-5606 flammable? |
YES under normal conditions. |
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CAVUMark Fri, 13 Feb 2009 06:14:48 GMT |
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| What are the seals used with MIL-H-5606? |
Buna-N (Nitrile) and Neoprene. |
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CAVUMark Fri, 13 Feb 2009 06:14:48 GMT |
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| What is the Flushing and cleaning agents of MIL-H-5606? |
Flushing: Naptha or Varsol, same and new clean fluid.
Cleaning: Stoddard |
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CAVUMark Fri, 13 Feb 2009 06:14:48 GMT |
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| What fluid is petroleum mineral based? What color is it dyed? |
MIL-H-5606 - RED in color. It is petroleum based with additives. |
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CAVUMark Fri, 13 Feb 2009 06:14:48 GMT |
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| Is MIL-H-7644 flammable? |
YES, highly. MIL-H-7644 is a vegetable based fluid very flammable. |
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CAVUMark Fri, 13 Feb 2009 06:10:50 GMT |
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| What is the compatible seal material with a vegetable based fluid? |
Natural Rubber |
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CAVUMark Thu, 19 Feb 2009 05:30:01 GMT |
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| What flushing and cleaning compounds are used on MIL-H-7644? |
MIL-H-7644 = Vegatable based fluid:
Flushing: Stoddard or same and new clean fluid.
Cleaning: Stoddard. |
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CAVUMark Wed, 15 Apr 2009 00:30:47 GMT |
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| What color is MIL-H-7644? |
This is a vegetable based fluid dyed blue. Mostly obsolete. |
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CAVUMark Fri, 13 Feb 2009 06:10:00 GMT |
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| Why are hydraulic fluids colored? Provide examples: |
To aid in identification.
Blue: MIL-H-7644
Red: MIL-H-5606
Purple: Skydrol 500 B-4, LD-4
Red: MIL-H83282 replaces Skydrol
Amber: MIL-H-4170 Type 1 |
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CAVUMark Thu, 19 Feb 2009 05:38:06 GMT |
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| What are the bases for Hydraulic fluids (4). |
Vegetable
petroleum - mineral
Synthetic - Hydrocarbon and Phosphate Ester |
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CAVUMark Fri, 13 Feb 2009 06:10:00 GMT |
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| What is the most important point to remember when servicing a A/Cs hydraulic systems? |
Always check with the airframe manufacturers maintenance manual for details on fluids, maintenance info, etc. |
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CAVUMark Fri, 13 Feb 2009 06:10:00 GMT |
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| What is viscosity? |
A fluids internal resistance to fluid flow.
Free flowing fluids have low viscosity.Excessively low viscosity will allow seal leaks. |
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CAVUMark Fri, 13 Feb 2009 06:10:00 GMT |
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| What are desirable qualities for hydraulic fluid? |
High fire point
High flash point
low heat of combustion
chemical stability
Minimum viscosity change with Temp.
Lubricity
Wide temperature range
Acceptable expansion and contraction with temp. |
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CAVUMark Fri, 13 Feb 2009 06:10:00 GMT |
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| Where are wipers used? Name the materials? |
Wipers clean and lube exposed parts of piston shafts. Metallic and felt materials. |
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CAVUMark Thu, 12 Feb 2009 05:06:23 GMT |
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| Name some gasket materials and their use. |
Asbestos- exhaust systems
copper - spark plugs
cork - oil seals, gap filler
rubber sheeting - compressible gasket, no oil or fuel contact. |
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CAVUMark Thu, 12 Feb 2009 05:06:23 GMT |
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| What is a U Ring and where are they used? |
Seals pressure in one direction, used in brake assemblies and master cylinders. Typically low pressure, < 1000psi. |
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CAVUMark Thu, 12 Feb 2009 05:06:23 GMT |
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| What is a V Ring and why are they special? |
One way seals, opening faces pressure. Requires male/female retainer to hold them in proper position. |
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CAVUMark Thu, 12 Feb 2009 05:02:26 GMT |
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| How are back up rings used, marked and inspected? |
They are typically Teflon, they are not color coded, but the bag is marked, inspection of scarf joint and surfaces is needed. Ring should not open more than 1/4 inch. |
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CAVUMark Thu, 12 Feb 2009 05:02:26 GMT |
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| How do you inspect an O Ring? |
With a 4 power magnifying glass, looking for nicks, cuts, scraps or cracks, irregularities, foreign particles. |
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CAVUMark Thu, 12 Feb 2009 05:02:26 GMT |
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| How are Packings marked? |
Color code or label in their container. Coding has no means to establish age. |
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CAVUMark Thu, 12 Feb 2009 05:02:26 GMT |
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| What O ring materials are adopted for use with MIL-H-5606 (Petroleum based) system? |
MS28775 series, good from -65F to 275F. Compatible material is Buna-N, Nitryl and Neoprene. |
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CAVUMark Fri, 13 Feb 2009 01:50:31 GMT |
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| What is the purpose of the O-ring? Good to what pressures? |
Prevent pressure in both directions. Good to 1500psi and above with a backing ring. Backing ring is placed on the side of the O-ring away from the pressure. |
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CAVUMark Thu, 12 Feb 2009 04:56:24 GMT |
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| What are packings, where are they used? What are some typical forms. |
Packings are used in systems with moving parts, pumps, selector valves, actuators, etc. Come in the form O-ring, V-ring, U-ring. |
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CAVUMark Thu, 12 Feb 2009 04:56:24 GMT |
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| What are the three main catagories of seals? |
Packing, gaskets, wipers. |
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CAVUMark Thu, 12 Feb 2009 04:56:24 GMT |
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| What are 4 criteria for a seal selection? |
1) Pressure
2) fluid
3) metal finish and clearance of parts
4) Type of motion - rotary or reciprocating |
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CAVUMark Thu, 12 Feb 2009 04:50:07 GMT |
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| Why are seals used? |
Seals prevent fluid from passing a certain point and keep dirt and air out of a system. |
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CAVUMark Thu, 12 Feb 2009 04:50:07 GMT |
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| How are lines marked containing fuel? toxic materials and physically dangerous materials such as O2. |
1) FLAM
2) TOXIC
3) PHDAN |
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CAVUMark Thu, 19 Feb 2009 05:30:36 GMT |
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| How are fluid lines identified in AC? |
Color codes, words and geometric. Symbols relate to the material in the tube and use? AC65-9A Page. 102. |
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CAVUMark Thu, 12 Feb 2009 04:50:07 GMT |
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| How is flexible hoses sized? |
in 1/16ths inch increments of inside diameter, similar to semi-rigid tubing and identical to the similar rigid tubing. |
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CAVUMark Thu, 12 Feb 2009 04:39:40 GMT |
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| What are the advantages of Teflon hoses? Describe the construction of flexible Teflon hose. |
They can handle most anything, including most fluids and pressures found in AC. Teflon tube is braided over with SST mesh for strength and protection. |
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CAVUMark Thu, 12 Feb 2009 04:39:39 GMT |
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| How are flexible hoses marked? |
They use lines, letters, numbers. Hoses compatible with phosphate ester Skydrol are so marked. |
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CAVUMark Thu, 12 Feb 2009 04:39:39 GMT |
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| What are the flexible hose pressure classifications? |
Low pressure - below 250psi.
Medium pressure - small hoses 1 wire braid, up to 3000psi. Larger hoses to 1500psi.
High pressure - all sizes up to 3000psi. |
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CAVUMark Thu, 19 Feb 2009 05:35:49 GMT |
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| How are flexible hoses constructed? |
A seamless synthetic rubber inner tube covered with layers of steel braid, and an outer layer of rubber impregnated cotton braid. |
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CAVUMark Thu, 19 Feb 2009 05:40:43 GMT |
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| What is Teflon and what fluids are compatible with it? |
Teflon is a DuPont trade name for tetrafluoroethylene resin. Compatible with nearly every substance or agent. |
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CAVUMark Thu, 12 Feb 2009 04:30:08 GMT |
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| What is Butyl and what fluids are compatible with it? |
It is a synthetic rubber flexible hose material made from petroleum raw materials. Do not use with petroleum products. Ok to use with phosphate ester based Skyrol - hydraulic fluid. |
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CAVUMark Thu, 12 Feb 2009 04:30:08 GMT |
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| What is Neoprene and what fluids are compatible with it? |
It is a synthetic flexible, acetyline base, hose material Less resistant to petroleum products than Buna-N. But better abrasion resistance. Do not use with phosphate ester based Skyrol - hydraulic fluid use with MIL-H-5606, petroleum based fluid. |
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CAVUMark Wed, 15 Apr 2009 00:27:52 GMT |
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| What is Buna -N and what fluids are compatible with it? |
It is a synthetic flexible hose material compatible with petroleum products. Do not use with Skyrol - hydraulic fluid. |
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CAVUMark Thu, 12 Feb 2009 04:30:08 GMT |
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| Name 4 materials that flexible hose are constructed of. |
Buna - N, Neoprene, Butyl, Teflon. |
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CAVUMark Thu, 12 Feb 2009 04:30:08 GMT |
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| Other than diameter and material what else is important to know about tubing? |
Tubing is also manufactured in various wall thicknesses. Know these as well. |
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CAVUMark Thu, 19 Feb 2009 05:33:19 GMT |
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| How is tubing sized? |
By the outside diameter dimension in 16ths. A number 6 tubing is 3/8", #8 is 1/2 inch. |
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CAVUMark Thu, 12 Feb 2009 02:42:13 GMT |
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| How is CRES tubing identified? |
Each includes manufacturer name, trademark, SAE number, and physical condition of metal. |
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CAVUMark Thu, 19 Feb 2009 05:38:45 GMT |
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| Where is CRES tubing used? |
Landing gear, flaps, brakes - high pressure hydraulic applications. External brakes lines should always be CRES. |
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CAVUMark Thu, 12 Feb 2009 02:42:13 GMT |
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| How is AL tubing marked for identification? |
Stamped on the surface (large tubing) or color coded on smaller diameter tubes. |
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CAVUMark Thu, 12 Feb 2009 02:37:38 GMT |
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| How can you determine between tubing materials: annealed austenitic and ferritic stainless steels. |
Magnet test. Austenitic are nonmagnetic and straight chromium carbon and low alloy steels are very magnetic. |
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CAVUMark Thu, 12 Feb 2009 02:37:38 GMT |
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| What is an advantage of CRES tubing over AL. |
It higher tensile strength means thinner wall thicknesses can be used so over all weight is slightly more than thicker wall AL tubing. |
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CAVUMark Thu, 12 Feb 2009 02:37:38 GMT |
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| What other tubing material is used? |
CRES with 3000 psi or greater, also in wheel wells or areas that see a lot of abuse. |
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CAVUMark Thu, 12 Feb 2009 02:31:14 GMT |
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| Is AL alloy a popular tubing? |
Yes. It is easily worked, resistant to corrosion and lightweight. |
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CAVUMark Thu, 19 Feb 2009 05:44:24 GMT |
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| Is copper a good tubing material? |
NO. It is being replaced by AL or CRES, SST. CU has a high fatique factor and hardens and becomes brittle from vibration and cracks. |
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CAVUMark Thu, 12 Feb 2009 02:31:14 GMT |
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| How is tubing sized when being replaced in a pressurized system? |
The same size tubing is installed, unless AD or some other directive calls for different. |
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CAVUMark Thu, 12 Feb 2009 02:31:14 GMT |
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